Flash lamp



Jan. 16, 1962 R. F. VANDEN BOOM ET AL 3,016,727

FLASH LAMP Filed April 2, 1959 Ihvervlrors 1 Robew t F. VandenBoom,

Rober -l: MAndevson, aw f? heiwggovneg.

nitd States atcnt 3,016,727 Patented Jan. 16, 1962 ice This invention relates in general to flash lamps of the type comprising a sealed radiation-transmitting bulb containing a quantity of combustible light-producing material and a combustion-supporting medium, such as an oxygenous gas, which enters into a reaction with the combustible material with the resulting emission of an instantaneous flash of actinic light of high intensity. More particularly, our invention relates to a midget or miniature size flash lamp of the above general type and to a terminal or base construction therefor.

Flash lamps as customarily made heretofore have generally been provided with base or terminal structures of a character such as to adapt the lamp for insertion in and removal from a cooperating lamp socket by a straight push-in and pull-out movement of the lamp in the direction of its axis. With the advant, however, of the very small size flash lamps which have become available recently, there exists the possibility or" so constructing the lamp as to lend itself to use in magazine type feeding or cartridge loading equipment employed with a camera wherein a number of the flash lamps are loaded into a magazine chamber and the line of lamps fed one at a time into firing position within the customary reflector of the flash equipment, following each firing of the foremost lamp in the line and ejection thereof from the magazine.

The base or terminal snucturm of flash lamps as customarily constructed heretofore also have generally comprised a separate conventional type lamp base member in the form of a metal shell which carries an insulated end contact and is cemented or otherwise secured to the glass bulb of the lam with the lead-in wires of the lamp connected to the shell and end contact of the base. The cost of such a lamp base, and the necessary basing operation involved in mounting it on the lamp bulb, adds a manufacturing cost to such prior type flash lamps which it is highly desirable to eliminate because of the fact that such lamps can only be used once and must then be discarded.

It is an object of our invention, therefore, to provide a flash lamp of the general type referred to which is particularly adapted to translatory indexing movement within a lamp-holding magazine or feeding chamber of a lamp flashing apparatus.

Another object of our invention is to provide a flash lamp of the type referred to having a relatively inexpensive baseless terminal construction particularly adapting the lamp to mounting in a lamp-holding magazine or feeding chamber of a lamp flashing apparatus for translatory indexing movement therethrough in a direction transversely of the lamp bulb axis.

According to one aspect of our invention, the glass envelope or bulb of the flash lamp is provided with a flat external stern press portion protruding from one end of the bulb and having a transverse guide means such as a channelway or groove formed in and extending completely across one of its flat sides, or a pair of such grooves formed in both of its flat sides and extending parallel to one another, and unobstructed from end to end so as to accommodate therein, and permit free sliding movement therethrough, of lamp guide track means provided within a lamp housing magazine or feeding chamber of a lamp flashing apparatus.

In accordance with a further aspect of the invention, I

the lamp lead-in wires are sealed through the stem press of the lamp envelope and have rigid terminal portions which extend outwardly from the end of the stem press and are retroverted or doubled back upon themselves to form open Wire loop contacts, the retroverted terminal portions of the lead-in wires having their free ends re entered and anchored within the end of the stem press so as to fixedly secure them in place against displacement. 3

According to a still further aspect of the invention, the double-leg wire loop terminal portions of the lead-in wires are bent around the end of the stern press, preferably to extend approximately parallel to and alongside the opposite flat sides thereof, and terminates short of the transverse guide means or channelways formed in the stern press so as to leave the same unobstructed for free passage therethrough of the lamp guide track means in the lamp magazine chamber of the lamp flashing apparatus.

Further objects and advantages of the invention will appear from the following detailed description of a species thereof and from the accompanying drawing.

In the drawing, FIG. 1 is an elevation, partly in section,

FIG. 4 is a sectional view through a suitable magazine type lampholder or feeding chamber of a lamp flashing apparatus and showing a flash lamp according to the invention mounted therein for sliding movement therethrough into firing position within the reflector (notshown) of the apparatus.

Referring to the drawing, the flash lamp'acco'rding to the invention comprises a sealed glass envelope or bulb 1 preferably of tubular shape and provided at one end with an external flattened stem press portion 2 protruding axially from the bulb. The bulb 1 of the particular flash lamp illustrated is of a size smaller than that employed in any flash lamp commercially available at present, the bulb having a volume of less than 2 cc. and preferably of the order of 1.2 cc., and the tubular portion of the bulb having an outside diameter of the order of A inch and a length of the order of ,4 inch. The opposite sides 3 of the stem press 2 are formed as flat surfaces preferably disposed approximately parallel to each other and to the axis of the bulb.

Sealed into the stem press end of the bulb 1 is a lamp ignition mount 4 comprising a pair of lead-in wires 5 which, in the manufacture of the lamp, are sealed into the stem press 2 so as to extend therethrough and into the bulb 1 in a direction approximately longitudinally of the bulb and in more or less side-by-side closely spaced relation. Interiorly of the bulb 1, the lead-in wires 5 are rigidly tied together and held in place by a support bead 6 of glass or other suitable insulating material in which the lead-in wires are embedded. The lead-in wires 5 terminate at their inner ends in the region of the bulb near the stem press end thereof and they are bridged at their said inner ends by an ignition filament 7 preferably consisting of a short straight length of fine tungsten wire having a diameter preferably of the order of 0.7 mil. The inner tips or ends of the lead-in wires 5 are provided with coatings or heads 8 of a suitable fulminating or primer material which beads 8 are in contact with the filament 7 and become ignited when the latter is energized and heated by the passage of an elec-- tric current therethrough. The fulminating material of which the primer beads 8 are composed preferably is of the general type disclosed and claimed in U.S. Patent 2,280,598, Meredith, issued April 21, 1942, and comprising an admixture of fine powders (i.e., of the order of 325 mesh or finer) of Zirconium, potassium perchlorate and No. 3 grade magnesium bonded together by a suitable binder such as a 2-5 solution of nitrocellulose in amyl acetate. For best results, however, and particularly where the ignition filament 7 is of a diameter of the order of 0.7 mil, it is preferred that the relative proportions of the above-named powder ingredients be within the particular ranges disclosed and claimed in US. Patent 2,756,577, Anderson, issued July 31, 1956, and assigned to the assignee of the present invention, such ranges being of the order of from 6090% zirconium, l8% magnesium and 9-35 potassium perchlorate.

The bulb 1 contains a filling of oxygen or other combustion-supporting gas and a quantity of combustible light-giving material 9 which, on ignition by the filament 7 and primer 8 constituting the ignition means of the lamp, enters into a reaction with the filling gas to produce a momentary flash of actinic light of high intensity suitable for picture-taking purposes. The combustible material 9 preferably consists of a loosely distributed quantity of filamentary strands of a suitable readily combustible' metallic material preferably consisting of zirconium or an alloy essentially composed of zirconium. Other suitable metallic materials, however, such as aluminum or magnesium or alloys of aluminum or magnesium, may be employed instead for the combustible material 9. The filamentary combustible material 9 preferably is in the form of fine cut strands of thin metallic foil of any of the above-mentioned compositions, the said fine cut strands being such as that commercially known as shredded foil and produced by the method and apparatus described and claimed in U.S. Patents 2,297,368 and 2,- 331,230, Rippl et al., such shredded foil strands having a width of the order of 1 mil and a thickness likewise of of the order of 1 mil. The filamentary combustible material 9 is distributed loosely within the bulb and as uniformly as possible throughout the space within the bulb above the ignition filament 7 in order to insure the most favorable combustion conditions for the said material.

. The pressure of the oxygen or other combustion-supporting gas filling within the bulb 1 should be sufiicient to insure the presence of suflicient oxygen or other gas to support the complete combustion of all the combustible material 9 present within the bulb. Thus, in the case of the preferred form of fiash lamp according to the invention wherein approximately 23 milligrams of Zirconium foil is employed as the combustible light-giving material 9 within a bulb 1 of the aforementioned size, a pressure of several atmospheres, e.g., around atmospheres, of oxygen or other combustion-supporting gas will insure the complete combustion of all the said shredded zirconium foil material. The oxygen or other combustionsupporting gas is preferably introduced into the bulb 1 through an exhaust tubulation at the top end of the bulb opposite the stem press end thereof, which exhaust tubulation, after the evacuation of the bulb therethrough and the introduction of the combustion-supporting gas into the bulb, is then sealed or tipped-off as indicated at 10 to thereby hermetically seal the bulb.

To strengthen the bulb 1 and render it substantially shatterproof on charge flashing, a suitable protective lacquer coating 11 such as cellulose acetate is applied to the outer side of the bulb, the inner side of the bulb being left bare or unprotected by a lacquer coating.

In accordance with the invention, the flash lamp is provided with a baseless terminal structure of a character such as to adapt the lamp for translatory indexing or advance movement laterally thereof within a lampholding magazine or feeding chamber of a lamp flashing apparatus, as well as to adapt the lamp for mounting in conventional type lamp-holding sockets by a straight push-in movement of the lamp into the socket in the direction of the lamp axis. of the lamp is provided with transversely extending gulde means 12 on one or both of the flat sides 3 of the stem press 4 defining a transverse guideway for sliding engagement with cooperating guide track means 13 of a lampholding magazine or feeding chamber 14 (FIG. 4). As shown, the guide means 12 on the lamp stem press 2 preferably comprises a straight channelway or groove formed in one, or in both of the flat side 3 of the stem press and extending completely thereacross, in a direction transversely of and preferably normal to the bulb axis, and unobstructed from end to end so as to permit free sliding movement therethrough of the slide track or guide rail means 13 of the lamp-holding magazine or feeding chamber 14 during the index movement of the lamp therethrough. Instead of being in the form of a guide channelway formed in the lamp stem press 2, the guide means 12 on the lamp may be in the form of a raised rib or rail on one or both fiat sides 3 of the stem press extending transversely thereacross. Where the guide means 12 on the stem press 2 comprises a pair of channelways or rails formed on the opposite flat sides 3 of the stem press, the two guide channelways or rails then should extend parallel to one another and preferably, in addition, are located abreast or directly opposite one another as shown, i.e., they are located at the same point lengthwise of the bulb axis.

The guide channelway or rail means 12 on the stem .press 2 is preferably so constructed as to have a close but free sliding fit with the cooperating guide track means 13 of the lamp holding magazine or feeding chamber 14 so that a series of the flash lamps mounted within the feeding chamber will be effectively supported and held in place more or less in a row within the magazine or feeding chamber, and so that each lamp will be guided through the magazine or feeding chamber in the .same relative position therein during the translatory index or feeding movement of the lamp. To this end, the outward side wall of each guide channelway 12 in the lamp stem press 2 is formed with a substantially flat wall portion 15 disposed in a plane normal to the bulb axis to thereby provide a sharp shoulder on the lamp stem press for enabling positive gripping or engagement thereof by the guide track means 13 to securely hold each lamp in place in the magazine or feed chamber 14 in the same predetermined position therein lengthwise of the lamp axis. In this manner, the terminal contacts 15 of each lamp are properly aligned with the electric current supply contacts 16 of the lamp socket portion of the lamp flashing apparatus so as to insure their contact therewith when each lamp is indexed to its furthest advanced position within the lamp magazine or feeding chamber 14.

Further in accordance with the invention, the lead-in wires 5 of the lamp are formed with relatively rigid or stiff outer terminal portions 17 which protrude endwise from the outer end 18 of the stem press 2 and serve as the terminal contacts of the lamp. For this purpose, the terminal portions 17 of the lead-in wires 5 may be advantageously constituted of approximately 16 mil diameter nickel-plated Dumet wire such as commonly employed in the lamp art for sealing into glass and comprising a copper-sheathed core of nickel iron alloy. Be-' cause of the resulting manufacturing cost-saving factor, the lead-in wires 5 are preferably made entirely of a one piece length of such 16 mil diameter nickel-plated Dumet wire since such wire will effectively seal into the conventional type soft glass of which the lamp bulb 1 and stem press 2 are made.

Outwardly of the stem press 2, the rigid terminal portions 1'7 of the lead-in wires 5 are retroverted or bent back upon themselves as indicated at 19 to form double-legged open loop-shaped contact members 20. The free ends 21 of the retroverted terminal portions of the lead-in wires are re-entered and embedded within the stem press 2, as

To this end, the stem press 2 I shown in FIG. 2, to thereby further anchor the wire loop contact terminals in place in, and rigidly support them from the stern press against distortion, as when engaged with the contacts of a lamp socket. To permit the making of the electrical contact to the lamp at the side of the stem press 2 as well as at the outer ends thereof, the wire loop contact members 20 are bent around the end of the stem press, preferably around the opposite flat sides 3 thereof, to provide side contact portions 23 extending approximately parallel to and alongside the opposite fiat sides 3 of the stem press in closely spaced relation thereto but terminating short of the respective guide means or channelway 12 so as to leave the same unobstructed for free passage therethrough of the guide track 13 of the lamp-holding magazine or feeding chamber 14. To allow for the normal variations in the location of the outer end 18 of the stem press 2, from lamp to lamp, owing to the difliculty of controlling the flow of plastic glass of the stem press during the formation thereof, the sideward bends 24 of the wire loop contact members 20 are formed a short distance, for instance inch or so from the outer end 18 of the stem press so as not to exert any stress thereon such as is likely to crack the glass thereof. In addition, the sideward bends 24- of the Wire loop contacts 20 are located a predetermined distance endwise of the stem press 2 from the flat side walls or reference shoulders 15 of the indexing or guide channelways 12 in the stem press in order to thereby insure the proper contacting of the wire loop contacts 20 with the lamp socket contacts of the lamp flashing apparatus in those cases where the socket contacts are adapted to engage with the said bends 24 in the wire loop contacts.

From the above description of the flash lamp according to the invention, it will be apparent that we have provided a lamp construction which is of simplified and inexpensive character as compared to prior conventional type flash lamps and which, in addition, is not only adapted for use with lamp sockets of the type into which the lamp is inserted by the conventional straight push-in movement of the lamp into the socket in the direction of the lamp axis, but which is also particularly adapted to translatory magazine feeding or index movement of the lamp, in a direction transversely of its axis, within a lamp-holding magazine or feeding chamber of a lamp flashing apparatus.

- Although a preferred embodiment of our invention has been disclosed, it will be understood that the invention is not to be limited to the specific construction and arrangement of parts shown, but that they may be widely modified within the spirit and scope of our invention as defined by the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

l. A flash lamp comprising a sealed glass bulb having a flat external stem press extending from one end thereof and provided with means defining an unobstructed guideway extending transversely of and completely across one of its flat sides for sliding engagement with cooperating slide track means of a lamp-holder, combustible lightproducing material within said bulb, a combustion-supporting gaseous filling in said bulb, and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through the stem press and rigid terminal portions extending outwardly from the end of said stem press, the said terminal portion of each of said lead-in wires being retroverted and having its free end re-entered and anchored within the end of said stern press.

2. A flash lamp comprising a sealed glass bulb having a flat external stem press extending from one end thereof and provided with a transverse guide channelway extending completely across one or" its flat sides and unobstructed from end to end, combustible light-producing material within said bulb, a combustion-supporting gaseous filling in said bulb, and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through the said stem press and rigid terminal portions extending outwardly from the end of said stem press, the said terminal portion of each of said lead-in wires being retroverted and having its free end re-entered and anchored within the end of said stem press, said terminal portion of each lead-in wire protruding from the stem press being bent around the end of and alongside said stem press but terminating short of the said transverse guide channelway therein so as to leave the same unobstructed.

3. A flash lamp comprising a sealed glass bulb having a flat external stem press extending from one end thereof and having parallel transverse guide channelways in its opposite flat sides extending completely thereacross and unobstructed from end to end, a quantity of combustible light-producing material Within said bulb, a combustionsupporting gaseous filling in said bulb, and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through the said stem press and rigid terminal portions extending outwardly from the end of said stem press, the said terminal portion of each of said leadin wires being retroverted and having its :free end reentered and anchored within the end of said stem press, the terminal portions of the lead-in wires protruding from the stem press being bent around the end thereof and extending approximately parallel to and closely adjacent opposite flat sides of said stem press but spaced therefrom and terminating short of the respective transverse guide channelways therein so as to leave the same unobstructed.

4. A flash lamp comprising a sealed glass bulb having a flat external stem press extending from one end thereof and having parallel transverse guide channelways in its opposite flat sides extending completely thereacr-oss and unobstructed from end to end, the sides of said channelways nearest the outer end of said stem press having substantially flat side wall portions disposed in a common plane approximately perpendicular to the said flat sides of the stern press, a quantity of combustible light-producing material within said bulb, a combustion-supporting gaseous filling in said bulb, and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through the said stem press and rigid terminal portions extending outwardly from the end of said stem press, the said terminal portion of each of said lead-in wires be ing retroverted to form a protruding open wire loop ter minal contact and having its free end re-entered and anchored within the end of said stem press, the said protruding wire loop contacts being bent laterally around the end of the stem press and extending approximately parallel to and alongside opposite fiat sides of said stem press but terminating short of the respective transverse guide channelways therein so as to leave the same unobstructed, the said lateral bends in said wire loop contacts being spaced endwise from the end of said stem press and being located a predetermined distance endwise of the stem press from the said flat side walls of said guide chan nelways.

5. A flash lamp comprising a bulb of tubular shape sealed at one end and provided with an external stern press having opposed fiat sides extending from the other end, said flat stem press being provided, in the opposed flat sides and intermediate its outer end and the portion connected to the bulb, with unobstructed parallel transverse slideways extending completely thereacross, the sides of the slideways nearest the outer end of the stem press having wall portions disposed in a common plane, a quantity of combustible light-producing material within said bulb, a combustion-supporting gaseous filling in said bulb and ignition means in said bulb for ingniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through said stem press and rigid terminal portions extending outwardly among? from the outer end of the stem press, said terminal portions of each of said lead-in wires having retroverted portions forming loops and each of said loops having two sideward bends spaced a short distance endwise from the outer end of the stem press, said loops being spaced at predetermined distance away from the flat sides of the stem press and terminating short of the said wall portions of the slideway so as to leave the slideway unobstructed.

6. A flash lamp comprising a bulb of tubular shape sealed at one end and provided with an external stem press having opposed flat sides extending from the other end, said flat stern press being provided, in the opposed flat sides and intermediate its outer end and the portion connected to the bulb, with unobstructed parallel transverse slideways extending completely thereacross, the sides of the slideways nearest the outer end of the stem press having wall portions disposed in a common plane, a quantity of combustible light-producing material within said bulb, a combustion-supporting gaseous filling in said bulb and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through said stem press and rigid terminal portions extending outwardly from the outer end of the stem press, the terminal portion of one of said lead-in wires having a retroverted portion with the free end of said one wire re-entered and anchored into the outer end of the stem press forming a first loop, the outwardly extending portion and the retroverted portion having sideward bends spaced at short distance endwise from the outer end of the stem press, said first loop extending approximately parallel to one of the fiat sides of the stem press but terminating short of one of the said wall portions of the slideway and being spaced from said one flat side of the stem press, and the terminal portion of the other of said lead-in wires having a retroverted portion with the free end of said other wire re-entered and anchored into the outer end of the stem press forming a second loop, the outwardly extending portion and the retroverted portion having sideward bends spaced a short distance endwise from the outer end of the stem press, said second loop extending approximately parallel to the other of the fiat sides of the stem press but terminating short of the other of the wall portions of the slideway and being spaced from said other flat side of the stem press.

7. A flash lamp comprising a bulb of tubular shape sealed at one end and provided with an external stem press .having opposed flat sides extending from the other end,

said flat stein press being provided, in the opposed fiat sides and intermediate its outer end and the portion connected to the bulb, with unobstructed parallel transverse slideways extending completely thereacross, the sides of the slideways nearest the outer end of the stem press having flat wall portions disposed in a common plane substantially perpendicular to the flat sides of the stem press, a quantity of combustible light-producing material within said bulb, a combustion-supporting gaseous filling in said bulb and ignition means in said bulb for igniting said combustible material, said ignition means including a pair of lead-in wires having portions sealed through said stern press and rigid terminal portions extending outwardly from the outer end of the stem press, the terminal portion of one of said lead-in wires having a retroverted portion with the free end of said one Wire re-entered and anchored into the outer end of the stem press forming a first loop, the outwardly extending portion and the retroverted portion having sideward bends spaced a short distance endwise from the outer end of the stem press, said first loop extending approximately parallel to one of the flat sides of the stern press but terminating short of one of the said flat wall portions of the slidcway and being spaced from said one flat side of the stem press, and the terminal portion of the other of said lead-in wires having a retroverted portion with the free end of said other wire rc-entered and anchored into the outer end of the stem press forming a second loop, the outwardly extending portion and the retroverted portion having sideward bends spaced at short distance endwise from the outer end of the stern press, said second loop extending approximately parallel to the other of the flat sides of the stem press but terminating short of the other of the flat wall portions of the slideway and being spaced from said other flat side of the stern press.

References Cited in the file of this patent UNITED STATES PATENTS 2,272,059 De Margitta Feb. 3, 1942 2,315,099 Van Liempt Mar. 30, 1943 2,672,039 Schwartz et a1 Mar. 16, 1954 2,894,383 Verbeek July 14,1959

FOREIGN PATENTS 217,453 Australia Sept. 25, 1958 1,156,184 France Dec. 9, 1957 

